They are both positively and negatively switched. It is was the method that involved the cheapest wiring to switch the lights in the combinations they wanted. (Least wires and least solenoids)

Obviously better off with the first wiring method as its easier to dim the spotlights with a simple switch to low beam. You just have to turn the spotties off before turning the lights off.

When the lights are off but in lowbeam postion they get partial negative power (enough for parkers) while highbeam position gets full power. Different spotlights will respond differently to the partial power.